9.B.235.  The Mitochondrial Outer Membrane Protein-14 (Om14) Family  

Proteomics on the outer membrane from yeast mitochondria suggest that most of these mitochondrial proteins have α-helical TMSs. These proteins are usually predicted to have a single α-helical TMS at either the N- or C-terminus, but more complex topologies are also seen. Burri et al. 2006 purified Om14 and found that it probably has 3 TMSs. It is encoded by the gene, YBR230c. Levels of the Om14 protein are much lower in cells grown on glucose than in cells grown on nonfermentable carbon sources. The α-helical outer membrane proteins presumably provide functions derived after the endosymbiotic event and require the translocase in the outer mitochondrial membrane complex (TC# 3.A.8) for membrane  insertion (Burri et al. 2006).